"That’s right, a lemon! I just cut it in half and use the actual lemon to scrub the hard water stains on any fixture. I’ve even used it to remove rust stains from a bobby pin I left sitting in the shower. Like I said, just rub the lemon on the fixture and rinse. The spots will magically disappear before your eyes and you’ll be left with this!"
Equal parts ammonia & hot water, a hot iron, and a towel to get stains out of carpet. :: Someone suggests in the comments that if you have pets follow it up with some vinegar so the pets don't think the lingering ammonia smell means it's a place to pee.